节点：AWS KMS 从内存中擦除公钥

Question

来自 KMS 操作的文档GenerateDataKey https://docs.aws.amazon.com/kms/latest/APIReference/API_GenerateDataKey.html

We recommend that you use the following pattern to encrypt data locally in your application:

Use the GenerateDataKey operation to get a data encryption key.

Use the plaintext data key (returned in the Plaintext field of the response) to encrypt data locally, then erase the plaintext data key from memory.

这段代码是否足以确保明文密钥在使用完毕后已从内存中删除。

const aws = require("aws-sdk");

const kms = new aws.KMS({...config});

(async () => {

    /** {Plaintext: Buffer, CiphertextBlob: Buffer} **/

    let dataKey = await kms.generateDataKey({...options}).promise();

    let encryptedString = MyEncryptionFunction(dataKey.Plaintext, "Hello World");

    dataKey.Plaintext.fill(0); //overwrite the buffer with zeroes to erase from memory;

})();

function MyEncryptionFunction(key, dataString) {

    let iv = crypto.randomBytes(16);

    let cipher = crypto.createCipheriv("aes256", key, iv);

    return cipher.update(dataString, "utf8", "hex") + cipher.final("hex");

}

假设 aws sdk 不会将密钥泄漏/复制到内存的其他部分是否安全，并且与createCipheriv内置加密库的功能相同，因此只需Plaintext用零覆盖缓冲区就足以从内存中擦除密钥？

Answer 1

这就是适用于 JavaScript 的 AWS 加密开发工具包所做的 [1]。事实上，如果加密 SDK 提供了您需要的功能，我会建议您使用它。aws-sdk 将此值视为敏感值，并在 Node.js[2] 中创建一个隔离的 Buffer。这意味着明文密钥的作用域是这个函数，只要它不共享它，就没有其他副本，也没有人可以访问。（通常的“没有坏人可以访问您的服务器”适用）跟踪节点 [3]..[4] 中的调用 createCipheriv 它将密钥的引用传递给 openSSL，而不是副本。[1] https://github.com/aws/aws-encryption-sdk-javascript/blob/master/modules/material-management/src/cryptographic_material.ts#L343[2] https://github.com/aws/aws-sdk-js/pull/2622/files[3] https://github.com/nodejs/node/blob/master/lib/crypto.js#L114[4] https://github.com/nodejs/node/blob/master/src/node_crypto.cc#L4099